Characterization of the human HCN1 channel and its inhibition by capsazepine. Export

@article{citeulike:303791, abstract = {The human hyperpolarization-activated cyclic nucleotide-gated 1 (hHCN1) subunit was heterologously expressed in mammalian cell lines (CV-1 and CHO) and its properties investigated using whole-cell patch-clamp recordings. Activation of this recombinant channel, by membrane hyperpolarization, generated a slowly activating, noninactivating inward current. The pharmacological properties of hHCN1-mediated currents resembled those of native hyperpolarization-activated currents (I(h)), that is, blockade by Cs(+) (99\% at 5 mm), ZD 7288 (98\% at 100 microm) and zatebradine (92\% at 10 microm). Inhibition of the hHCN1-mediated current by ZD 7288 was apparently independent of prior channel activation (i.e. non-use-dependent), whereas that induced by zatebradine was use-dependent. The VR1 receptor antagonist capsazepine inhibited hHCN1-mediated currents in a concentration-dependent (IC(50)=8 microm), reversible and apparently non-use-dependent manner. This inhibitory effect of capsazepine was voltage-independent and associated with a leftward shift in the hHCN1 activation curve as well as a dramatic slowing of the kinetics of current activation. Elevation of intracellular cAMP or extracellular K(+) significantly enhanced aspects of hHCN1 currents. However, these manipulations did not significantly affect the capsazepine-induced inhibition of hHCN1. The development of structural analogues of capsazepine may yield compounds that could selectively inhibit HCN channels and prove useful for the treatment of neurological disorders where a role for HCN channels has been described.}, address = {Neurology \& GI CEDD, GlaxoSmithKline, New Frontiers Science Park North, Third Avenue, Harlow, Essex CM19 5AW.}, author = {Gill, C. H. and Randall, A. and Bates, S. A. and Hill, K. and Owen, D. and Larkman, P. M. and Cairns, W. and Yusaf, S. P. and Murdock, P. R. and Strijbos, P. J. and Powell, A. J. and Benham, C. D. and Davies, C. H.}, citeulike-article-id = {303791}, citeulike-linkout-0 = {http://dx.doi.org/10.1038/sj.bjp.0705945}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/15351778}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=15351778}, doi = {10.1038/sj.bjp.0705945}, issn = {0007-1188}, journal = {Br J Pharmacol}, keywords = {capsazepine, hcn}, month = {October}, number = {3}, pages = {411--421}, posted-at = {2005-08-25 13:58:33}, priority = {2}, title = {Characterization of the human HCN1 channel and its inhibition by capsazepine.}, url = {http://dx.doi.org/10.1038/sj.bjp.0705945}, volume = {143}, year = {2004} }

TY - JOUR ID - citeulike:303791 L3 - citeulike-article-id:303791 N2 - The human hyperpolarization-activated cyclic nucleotide-gated 1 (hHCN1) subunit was heterologously expressed in mammalian cell lines (CV-1 and CHO) and its properties investigated using whole-cell patch-clamp recordings. Activation of this recombinant channel, by membrane hyperpolarization, generated a slowly activating, noninactivating inward current. The pharmacological properties of hHCN1-mediated currents resembled those of native hyperpolarization-activated currents (I(h)), that is, blockade by Cs(+) (99% at 5 mm), ZD 7288 (98% at 100 microm) and zatebradine (92% at 10 microm). Inhibition of the hHCN1-mediated current by ZD 7288 was apparently independent of prior channel activation (i.e. non-use-dependent), whereas that induced by zatebradine was use-dependent. The VR1 receptor antagonist capsazepine inhibited hHCN1-mediated currents in a concentration-dependent (IC(50)=8 microm), reversible and apparently non-use-dependent manner. This inhibitory effect of capsazepine was voltage-independent and associated with a leftward shift in the hHCN1 activation curve as well as a dramatic slowing of the kinetics of current activation. Elevation of intracellular cAMP or extracellular K(+) significantly enhanced aspects of hHCN1 currents. However, these manipulations did not significantly affect the capsazepine-induced inhibition of hHCN1. The development of structural analogues of capsazepine may yield compounds that could selectively inhibit HCN channels and prove useful for the treatment of neurological disorders where a role for HCN channels has been described. IS - 3 JF - Br J Pharmacol SN - 0007-1188 AD - Neurology & GI CEDD, GlaxoSmithKline, New Frontiers Science Park North, Third Avenue, Harlow, Essex CM19 5AW. EP - 421 TI - Characterization of the human HCN1 channel and its inhibition by capsazepine. VL - 143 SP - 411 KW - capsazepine KW - hcn AU - Gill, CH AU - Randall, A AU - Bates, SA AU - Hill, K AU - Owen, D AU - Larkman, PM AU - Cairns, W AU - Yusaf, SP AU - Murdock, PR AU - Strijbos, PJ AU - Powell, AJ AU - Benham, CD AU - Davies, CH PY - 2004/10// UR - http://dx.doi.org/10.1038/sj.bjp.0705945 ER -